I think you have 3 choices here: push, bet 6k w/ intent to play a stop and go, or limp w/ intent to move-in on any pre-flop raise and if called to lead the flop w/ a pot sized bet on a whiff and a min bet if you hit (to make it look like a delayed steal). Which one I'd pick would be based on what I'd seen him do and what he'd seen me do. At this point I'm OK w/ getting my chips in the middle since I'm looking to win it so: if I'd seen him aggressively defend his blinds I'd push (or if I'd already pushed and not shown recently); if he'd played weak/tight pre or post-flop I'd go w/ the stop and go; if he'd played LAGGY I'd limp.